A proportional valve device having dual linked valve members in a single housing is known from U.S. Pat. No. 4,452,267, incorporated herein by reference. The valve structure in that known valve device is controlled by an electromagnet. The armature of the electromagnet actuates a first valve which is coupled by a valve rod to a second valve. The controlling of the flows of pressure fluid which are to be governed by this valve are effected exclusively by way of the electromagnet. This arrangement has the disadvantage that the open cross section of the valve cannot be set in a dependably reproducible manner due to temperature variations and possibly also due to the forces of flow and static pressure of the pressure fluid, since there is no possibility of feedback or position sensing as to the open cross section of the valve.
Federal Republic of Germany laid-open patent application DE OS 29 42 900 A1, incorporated herein by reference, relates to a valve device in which the position of the valve rod is detected by a sensor device. The valve rod is in this case connected to a position detector which is displaced together with the valve rod, upon actuation of the valve rod and thus a change in the valve position. In this manner, the position of the valve members may be detected via a position detector. The position detector is in this case arranged within a housing which is integrated into the entire valve structure. This has the disadvantage that this additional housing increases the axial length of the valve device. Such an arrangement, because of this increase of size, cannot be used in the implementation of valves which are compact.